| PATENT NUMBER | This data is not available for free |
| PATENT GRANT DATE | December 20, 1994 |
| PATENT TITLE |
Biodegradable disposable diaper |
| PATENT ABSTRACT | A biodegradable disposable diaper comprising a combination of a liquid absorbing material, a liquid permeable surface material and an leakproof backing material, said liquid permeable material being formed of an aliphatic polyester resin obtained by reacting an aliphatic saturated polyester prepolymer having an end group which is materially a hydroxyl group with a coupling agent or formed of said aliphatic polyester resin and an aliphatic saturated polyester resin which has not been treated by said coupling agent. The disposable diaper has excellent mechanical strength, softness, feel of touch, productivity as well as biodegradability, air permeability and waterproofness |
| PATENT INVENTORS | This data is not available for free |
| PATENT ASSIGNEE | This data is not available for free |
| PATENT FILE DATE | April 20, 1993 |
| PATENT CLAIMS |
What is claimed is: 1. A biodegradable disposable diaper comprising, in order, a liquid permeable surface material, a liquid absorbing material, and a leakproof backing material, wherein said liquid permeable surface material is attached to said liquid absorbing material, and said liquid absorbing material is attached to said leakproof backing material, wherein said liquid permeable surface material and said leakproof backing material are (1) formed of an aliphatic polyester resin obtained by reacting an aliphatic saturated polyester prepolymer having an end group which is a hydroxyl group with a coupling agent or (2) formed of (A) an aliphatic polyester resin obtained by reacting an aliphatic saturated polyester prepolymer having an end group which is a hydroxyl group with a coupling agent and (B) an aliphatic saturated polyester resin which has not been treated by said coupling agent, wherein the leakproof backing material is made from less coupling agent than the liquid permeable surface material. 2. A biodegradable disposable diaper as claimed in claim 1, wherein the leakproof backing material made of aliphatic polyester resin is a non-woven fabric. 3. A biodegradable disposable diaper as claimed in claim 2, wherein the leakproof backing material made of aliphatic polyester resin is a non-woven fabric formed by mixing fibers or laminating webs formed by a spun-bond method and melt-blown method. 4. A biodegradable disposable diaper as claimed in any one of claims 1 to 3, wherein a non-woven fabric is used as said liquid permeable surface material, said non-woven fabric being formed (1) from non-woven fabric formed by a dry method, spun bond method, thermal bond method, stitch bond method or needle punch method using an aliphatic saturated polyester treated with a coupling agent or (2) from (A) non-woven fabric formed by a dry method, spun bond method, thermal bond method, stitch bond method, or needle punch method using an aliphatic saturated polyester treated with a coupling agent and (B) filaments or non-woven fabric formed by a melt-blown method using an aliphatic saturated polyester resin, which has been treated with a coupling agent or which has not been treated with a coupling agent. |
| PATENT DESCRIPTION |
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disposable diaper in which biodegradable non-woven polyester fabric is used as a liquid permeable surface material and as an leakproof backing material. More particularly, the present invention is concerned with a disposable diaper which is not only excellent in mechanical strength, softness, waterproofness, air permeability and feel of touch but is wholly biodegradable. 2. Discussion of the Background In recent years, disposable diaper is finding remarkably spreading use, and is facing diversified demands in regard to the quality. Various improvements have been achieved in the constructions of disposable diapers. However, most of disposable diapers consist of a liquid permeable surface portion which contacts with the user's skin and which is generally referred to as "cover stock", a liquid absorbing portion made of fluffed pulp containing high absorbency polymer, and an leakproof backing portion for preventing water leakage generally referred to as "back sheet". Papers were used in some old-type disposable diapers. Nowadays, however, non-woven cloths made by thermal bond method or spun-bond method are used in most disposable diapers. On the other hand, leakproof backing material is required to excel in leakproof performance (waterproofness), softness and moisture permeability to release the internal moisture to the exterior, as well as large tear or breakage strength. It is also required not to make rustling noise. Conventionally, the leakproof backing material has been made of a material such as a film of plasticized polymer such as polyvinyl chloride, low-density polyethylene, polypropylene, polyurethane, ethylene-vinyl acetate copolymer, ethylene-(meta)acrylic acid ester copolymer or the like, or a film which is formed by mixing a filler such as calcium carbonate in the above-mentioned film, stretched the film so as to generate micro-pores, and effecting satin-like embossing on the film. Thus, in the known disposable diaper, the liquid permeable surface material and the leakproof backing material are not biodegradable, although the liquid absorbing material made of fluffed pulp exhibits biodegradability. Consequently, when the diaper is disposed into the ground, the surface material and the backing material remain without being degraded. For the purpose of complete disposal, therefore, it has been necessary to burn the whole diaper or to separate the liquid-permeable surface material and the leakproof backing material from the top sheet layer for separate disposal. An object of the present invention is to develop a biodegradable disposable diaper in which a biodegradable liquid-permeable surface material and a biodegradable leakproof backing material are used in combination and which exhibits superior mechanical strength, softness, feel of touch and waterproofness, as well as high productivity. It is also an object of the present invention to develop a biodegradable disposable diaper to which air-permeability is imparted without reducing waterproofness. It is also an object of the present invention to provide a diaper having top layer of an extremely good feel of touch. SUMMARY OF THE INVENTION To these ends, according to the invention, there is provided a biodegradable disposable diaper comprising a combination of a liquid-absorbing material, a liquid-permeable surface material and an leakproof backing material. The liquid-permeable material and leakproof material are formed of an aliphatic polyester resin obtained by reacting an aliphatic saturated polyester prepolymer having an end group which is materially |
| PATENT EXAMPLES | available on request |
| PATENT PHOTOCOPY | available on request |
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